Nowadays

the measurement for radon concentration and radon daughters potential ɑ energy concentration has gained more and more attention.This paper introduces the basic principle for ’Markov’ method in details.A hardware and software of the radon measure instrument by balloon has also been described.This system integrated Au-Si surface barrier detector and dc vacuum pump and designed a pneumatic switch valve.With the switch valve

the direction of gas path can be changed conveniently without the balloon being taken down.This instrument has an internal temperature and humidity sensor and ARM7 microprocessor as the logic core.It can store 2000 groups of data in the system.Meanwhile this Radon instrument has been tested in standard radon chamber of South China University and the results showed that the new developed balloon method measure radon apparatus could be applicable because of its easy use

great reliability and performance stability.